﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace week3
{
    class CopyFileAddLineNumber
    {
//hello world
        public void Sayhello()//main hello
        {
            Console.WriteLine("Hello world ！！！");
            Console.ReadLine();
        }
    }
}
